I have an above ground pool 18 foot circular, 48 inches deep. never had much of a problem with the pool for the past 8 year but this year sudddenly the wayer smeels bad. it has a strong metallic oder. I did have the water tested and they said it's perfect, yet the water is a little cloudy and green and ofcourse the smell is bad. I have vacuumed to get the algae out. But even in the past with algae I never had an issue with my pool smelling. Any ideas?